Turbine engines are used as the primary power source for various kinds of aircraft. The engines may also be used as auxiliary power sources to drive air compressors, hydraulic pumps, and for industrial gas turbine (IGT) power generation. Further, the power from turbine engines is used for stationary power supplies such as backup electrical generators for hospitals and the like.
Most turbine engines generally follow the same basic power generation procedure. Air is ingested into a fan section, and directed into a compressor section to be compressed. The compressed air is mixed with fuel and burned, and the expanding hot combustion gases are directed against stationary turbine vanes in the engine. The vanes turn the high velocity gas flow partially sideways to impinge on the turbine blades mounted on a rotatable turbine disk. The force of the impinging gas causes the turbine disk to spin at high speed. Jet propulsion engines use the power created by the rotating turbine disk to draw more air into the engine and the high velocity combustion gas is passed out of the gas turbine aft end to create forward thrust.
To draw air into the engine fan section in a desired manner, stator vanes are typically disposed therein. When the air passes over the stator vanes, sand, dust, and other air-borne particulate that may be present therein, may impinge the vanes. Over an extended period of time, the vanes may become eroded, which may lead to a decreased life cycle of the turbine engine (i.e., their premature removal). To minimize erosion, the stator vanes are typically coated with an erosion-protective coating.
Because lighter components generally allow for increased engine efficiency, aircraft components are preferably made of lightweight materials. However, manufacturing lightweight, erosion-resistant stator vanes has presented certain challenges. For example, lightweight polymer matrix fiber composites, useful for making uncoated stator vanes, generally have melting points, glass transition temperatures, or maximum exposure temperatures that are significantly lower than that of the erosion-protective coating material (e.g. below 150° C.). Consequently, conventionally used deposition processes, which are typically performed at temperatures above 200° C., and often at temperatures above 500° C., have not been useful. Moreover, the conventionally used deposition processes do not produce coatings that suitably adhere to and protect the stator vanes.
Accordingly, there is a need for a coating process that produces suitable erosion-protective coatings on aircraft components. Moreover, it is desirable for the coating process to be relatively inexpensive and simple to perform. Additionally, it is desirable for the coating process to be easily implemented into existing component manufacturing processes.